The present invention relates to a lens driving apparatus used for information recording (information writing) into an information recording medium or information reproducing (information reading) from the information recording medium, and an apparatus and method of manufacturing the lens driving apparatus.
In order to optically perform information recording or information reproducing to a disk-shaped information recording medium such as CD (Compact Disk), DVD (Digital Video Disk or Digital Versatile Disk) or MD (Mini Disk), it is necessary to accurately follow an objective lens to an information track of the information recording medium. For this purpose, a so-called pickup apparatus is provided with a lens driving apparatus for electromagnetically driving the objective lens in a focusing direction and a tracking direction to perform positioning control.
FIG. 10 is a perspective view showing a configuration of a conventional lens driving apparatus provided in a pickup apparatus. This lens driving apparatus comprises a lens holder 2 in which an objective lens 1 is mounted and a substrate 7 for cantilevering the lens holder 2 by four elastic wires 3, 4, 5, 6.
While one ends of the respective elastic wires 3, 4, 5, 6 are coupled to four corners of the lens holder 2, the other ends of the elastic wires 3, 4, 5, 6 are coupled to the substrate 7 through gaps defined by depression stepped portions 8, 9, 10, 11 provided in four corners of the substrate 7 and opposed pieces 12, 13, and further the gaps are filled with ultraviolet cure resins 14, 15, 16, 17 acting as a damping material which damps mechanical vibrations.
Further, as shown in a schematic side view of FIG. 11, a magnet 18 and yokes 19, 20 fixed in the substrate 7 and an electric circuit board 21 fixed in the lens holder 2 are provided between the lens holder 2 and the substrate 7, and a focusing coil and a tracking coil (not shown) are formed on the electric circuit board 21. Also, the electric circuit board 21 in which the focusing coil and the tracking coil are formed is provided between the yokes 19 and 20 at a certain distance.
Then, magnetic force is generated in a focusing direction xcex8F by supplying a driving current to the focusing coil and focusing control is performed by finely adjusting a position of the focusing direction xcex8F of the objective lens 1 and the lens holder 2 by means of this magnetic force. Also, magnetic force is generated in a tracking direction xcex8T by supplying a driving current to the tracking coil and tracking control is performed by finely adjusting a position of the tracking direction xcex8T of the objective lens 1 and the lens holder 2 by means of this magnetic force.
Here, the lens holder 2 is cantilevered to the substrate 7 through the four elastic wires 3, 4, 5, 6, so that the lens holder 2 becomes deformed freely in response to the magnetic force generated in the case of the focusing control and the tracking control. As a result of this, the objective lens 1 and the lens holder 2 are deviated in a desired direction with them floated and thus, information recording into an information recording medium DSC or information reproducing from the information recording medium DSC can be performed with high accuracy.
Also, the elastic wires 3, 4, 5, 6 are fixed in the substrate 7 while being buried in a state surrounded by the ultraviolet cure resins 14, 15, 16, 17 acting as a damping material, so that the ultraviolet cure resins 14, 15, 16, 17 absorb vibrations occurring in the elastic wires 3, 4, 5, 6 in the case of the focusing control and the tracking control, and it is constructed so as to achieve the focusing control and the tracking control with good responsiveness.
Incidentally, as shown in FIG. 11, the substrate 7 is mounted on a movable body 24 supported by a pair of guide shafts 22, 23 provided in a chassis of a body of an information recording and reproducing apparatus. Then, by forward or backward moving the movable body 24 along a longitudinal direction of the guide shafts 22, 23, this lens driving apparatus is forward or backward moved in a radial direction of the information recording medium DSC (the same direction as the tracking direction xcex8T) and further by making use in combination with the focusing control and the tracking control, it is intended to perform the information recording and information reproducing with high accuracy.
However, in the conventional lens driving apparatus described above, as shown in FIG. 10, liquid sagging occurs in case of simply filling the depression stepped portions 8, 9, 10, 11 of the substrate 7 with the ultraviolet cure resins 14, 15, 16, 17, so that the opposed pieces 12, 13 other than the substrate 7 were mounted so as to attach to the depression stepped portions 8, 9, 10, 11 and thereby the gaps capable of preventing the liquid sagging were defined and their gaps were filled with the ultraviolet cure resins 14, 15, 16, 17. Because of this, there were problems that the number of manufacturing steps increases while the number of parts increases. These problems will be described in detail with reference to FIGS. 12 and 13 below.
First, as shown in an exploded perspective view of FIG. 12, the substrate 7 and the opposed pieces 12, 13 are respectively molded by individual members. Depression stepped portions 7c, 7d, 7e, 7f for inserting the elastic wires 3, 4, 5, 6 are molded in the four corners of the substrate 7, and fitting protrusions 7g, 7h are formed on the side end of a T-shaped projection 7b of the side of the depression stepped portions 7e, 7f and fitting protrusions (not shown) similar to the fitting protrusions 7g, 7h are formed on the side end of a T-shaped projection 7a of the side of the depression stepped portions 7c, 7d. 
A through hole 13a for fitting the fitting protrusions 7g, 7h is formed in the opposed piece 13 and a through hole 12a similar to the through hole 13a is formed in the opposed piece 12.
Next, as shown in a plan view of FIG. 13, after inserting the elastic wires 3, 4, 5, 6 into the depression stepped portions 7c, 7d, 7e, 7f, the elastic wires 3, 4, 5, 6 were supported in the substrate 7 by fixing respective rear ends of the elastic wires 3, 4, 5, 6 with adhesive and then, the opposed pieces 12, 13 were fitted to the projections 7a, 7b and the gaps defined thereby were filled with the liquid ultraviolet cure resins 14, 15, 16, 17 and the resins were cured.
In this manner, the opposed pieces 12, 13 were mounted in order to prevent the ultraviolet cure resins 14, 15, 16, 17 from flowing out of the depression stepped portions 7c, 7d, 7e, 7f in a state of liquid, so that there were problems that the number of manufacturing steps increases while the number of parts increases.
The invention is implemented to overcome the problems of the conventional art, and it is an object of the invention to provide a lens driving apparatus, an apparatus and method of manufacturing the lens driving apparatus capable of reducing the number of parts and simplifying manufacturing steps.
In order to achieve the object, a lens driving apparatus of the invention is characterized in that the lens driving apparatus has a lens holder for holding an objective lens, and a substrate which supports the lens holder through elastic members and is molded with resin, and the elastic members are integrally supported in the substrate in the case of the resin molding and are provided within gaps molded in the substrate with the gaps ranging to the integrally supported portions and are buried in a damping material with which the gaps are filled.
Also, the lens driving apparatus is characterized in that the gaps are formed by depression portions and projection portions opposed one another molded in the proximity of the elastic members in the case of the resin molding.
Further, the lens driving apparatus is characterized in that the depression portions and projection portions are molded in a long shape along a longitudinal direction of the elastic members.
According to the lens driving apparatus of such a construction, while the substrate is integrally molded by the resin molding, the elastic members are also integrally supported in the substrate. Further, the elastic members are provided within the gaps integrally molded in the substrate by the resin molding and also are buried with the elastic members surrounded by the damping material with which the gaps are filled. Thus, the lens driving apparatus manufactured while reducing the number of parts and the number of manufacturing steps can be provided. In addition, the lens driving apparatus without liquid sagging of the damping material can be provided by filling the gaps within which the elastic members are provided with the damping material. For example, the lens driving apparatus without the liquid sagging can be provided even when using ultraviolet cure resin as the damping material.
Also, a lens driving apparatus of the invention is characterized in that the lens driving apparatus has a lens holder which holds an objective lens and is molded with resin, and a substrate for supporting the lens holder through elastic members, and the elastic members are integrally supported in the lens holder in the case of the resin molding and are provided within gaps molded in the lens holder with the gaps ranging to the integrally supported portions and are buried in a damping material with which the gaps are filled.
Also, the lens driving apparatus is characterized in that the gaps are formed by depression portions and projection portions opposed one another molded in the proximity of the elastic members in the case of the resin molding.
Further, the lens driving apparatus is characterized in that the depression portions and projection portions are molded in a long shape along a longitudinal direction of the elastic members.
According to the lens driving apparatus of such a construction, while the lens holder is integrally molded by the resin molding, the elastic members are also integrally supported in the lens holder. Further, the elastic members are provided within the gaps integrally molded in the lens holder by the resin molding and also are buried with the elastic members surrounded by the damping material with which the gaps are filled. Thus, the lens driving apparatus manufactured while reducing the number of parts and the number of manufacturing steps can be provided. In addition, the lens driving apparatus without liquid sagging of the damping material can be provided by filling the gaps within which the elastic members are provided with the damping material. For example, the lens driving apparatus without the liquid sagging can be provided even when using ultraviolet cure resin as the damping material.
A manufacturing apparatus of a lens driving apparatus of the invention is characterized in that there is the manufacturing apparatus of the lens driving apparatus having a lens holder for holding an objective lens, and a substrate for supporting the lens holder through elastic members, and the manufacturing apparatus comprises a mold on which cavities having a first depression for molding a base of the substrate, a projection adjacent to the first depression, and a second depression adjacent to the projection and partially ranging to the first depression are formed, and by filling the cavities of the mold with synthetic resin with the elastic members stretched between the projection of the mold and the ranging portion of the first and second depressions, the elastic members are supported in the base molded by the synthetic resin with which the ranging portion is filled and are provided within gaps formed by the projection and thereafter are buried in a damping material by filling the gaps with the damping material.
Also, a manufacturing apparatus of a lens driving apparatus is characterized in that there is the manufacturing apparatus of the lens driving apparatus having a lens holder for holding an objective lens, and a substrate for supporting the lens holder through elastic members, and the manufacturing apparatus comprises a mold on which cavities having a first depression for molding a base of the lens holder, a projection adjacent to the first depression, and a second depression adjacent to the projection and partially ranging to the first depression are formed, and by filling the cavities of the mold with synthetic resin with the elastic members stretched between the projection of the mold and the ranging portion of the first and second depressions, the elastic members are supported in the base molded by the synthetic resin with which the ranging portion is filled and are provided within gaps formed by the projection and thereafter are buried in a damping material by filling the gaps with the damping material.
According to the manufacturing apparatus of the lens driving apparatus, while the substrate or the lens holder is integrally molded by the resin molding, the elastic members are also integrally supported in the substrate or the lens holder. Further, the elastic members are provided within the respective gaps integrally molded in the substrate or the lens holder by the resin molding and also are buried with the elastic members surrounded by the damping material with which the gaps are filled. Thus, the lens driving apparatus manufactured while reducing the number of parts and the number of manufacturing steps can be provided. In addition, the lens driving apparatus without liquid sagging of the damping material can be provided by filling the gaps within which the elastic members are provided with the damping material. For example, the lens driving apparatus without the liquid sagging can be provided even when using ultraviolet cure resin as the damping material.
A manufacturing method of a lens driving apparatus of the invention is characterized in that there is the manufacturing method of the lens driving apparatus having a lens holder for holding an objective lens, and a substrate for supporting the lens holder through elastic members, and the manufacturing method comprises a first step of fitting the elastic members into a mold on which cavities having a first depression for molding a base of the substrate, a projection adjacent to the first depression, and a second depression adjacent to the projection and partially ranging to the first depression are formed with the elastic members stretched between the projection and the ranging portion of the first and second depressions, a second step of integrally supporting the elastic members in the base molded by the synthetic resin with which the ranging portion is filled and providing the elastic members within gaps formed by the projection between the first and second depressions by filling the cavities of the mold with synthetic resin, and a third step of burying the elastic members in a damping material by filling the gaps with the damping material after separating the mold.
Also, a manufacturing method of a lens driving apparatus is characterized in that there is the manufacturing method of the lens driving apparatus having a lens holder for holding an objective lens, and a substrate for supporting the lens holder through elastic members, and the manufacturing method comprises a first step of fitting the elastic members into a mold on which cavities having a first depression for molding a base of the lens holder, a projection adjacent to the first depression, and a second depression adjacent to the projection and partially ranging to the first depression are formed with the elastic members stretched between the projection and the ranging portion of the first and second depressions, a second step of integrally supporting the elastic members in the base molded by the synthetic resin with which the ranging portion is filled and providing the elastic members within gaps formed by the projection between the first and second depressions by filling the cavities of the mold with synthetic resin, and a third step of burying the elastic members in a damping material by filling the gaps with the damping material after separating the mold.
According to the manufacturing method of the lens driving apparatus, while the substrate or the lens holder is integrally molded by the resin molding, the elastic members are also integrally supported in the substrate or the lens holder. Further, the elastic members are provided within the respective gaps integrally molded in the substrate or the lens holder by the resin molding and also are buried with the elastic members surrounded by the damping material with which the gaps are filled. Thus, the lens driving apparatus manufactured while reducing the number of parts and the number of manufacturing steps can be provided. In addition, the lens driving apparatus without liquid sagging of the damping material can be provided by filling the gaps within which the elastic members are provided with the damping material. For example, the lens driving apparatus without the liquid sagging can be provided even when using ultraviolet cure resin as the damping material.